The use of various antioxidant compositions for counteracting the deleterious effect of free radicals upon cells of the human body is widely studied. Free radicals are implicated in a wide variety of diseases of the human body. Referring particularly to diseases of the skin, the presence of free radicals on the skin results from a number of conditions, including over-production of free radicals within the cell itself, or exposure to external forces such as ultraviolet rays, coupled with an inability of the cell itself to defend against the over-production. The resulting excess of free radicals is known to be the cause of various skin disabilities, such as wrinkling, lack of elasticity, and generalized aging, and there is a need to fortify and supplement the various antioxidant mechanisms in the body.
Many compositions have been proposed and used in the past for providing the desired antioxidant effect, including Vitamin E (tocopherol), Vitamin A (beta-carotene), Vitamin C (ascorbic acid), Trolox (a Vitamin E analog), and the like. In addition, certain plant extracts have been reported as having antioxidant properties, including extracts from birch Betula platyphylla) (JP-A-10-046143) and various plant extracts obtained by extraction, with water or a lower alcohol or an aqueous lower alcohol solution, of plants such as hibiscus, aloe, rhubarb, osei (polygonati rhizoma), bearberry leaf, enmeiso (plectranthi herba), yobaihi (nyricae cirtex), pueraria root, cnidium rhizome, atractylodes lancea rhizome, mentha leaf, glycyrrhiza, peony root, coix seed, sin'i (magnoliae flos), cinnamon bark, houttuynia herb, coptis rhizome, moutan bark, gentian, nutgall, swertia herb, geranium herb, phellodendron bark, dried ginger, scutellaria root, chulling (poly porus), garlic, sage, oregano, rosemary, laurel, celery, thyme, tarragon, nutmeg, mace, clove, Japanese horseradish, savory, basil, red pepper, roasted bean, black tea, green tea, persimmon leaf, coffee, horsetail, henon bamboo, mugwort, Cynostemma species, low striped bamboo, matrimony vine, Cyrtomium species, and shiitake mushrooms (JP-A6-024937). [See US published patent application Publication No. 2004/0028643].
Personal care products such as body washes, lotions, liquid hand soaps, sunscreens, shampoos, and the like ordinarily contain a variety of additives designed to provide performance enhancing benefits such as moisturizing, fragrance, colorant, anti-inflammatory, and anti-irritant properties, and thus these personal care products provide a convenient vehicle for also applying antioxidants directly to the skin. Botanical extracts are a source for many of the above performance enhancing properties and accordingly are conventionally found as additives to the personal care products. To keep the number of additives within reasonable bounds with respect to any particular skin care product, it would be desirable to use herb extracts that provide not only one or more of the performance enhancing properties but also an antioxidant property, and, more particularly, it would be beneficial to find combinations of herb extracts that provide synergistic antioxidant effects. That is, it would be useful to provide formulations of different herb extracts that would function synergistically to increase the total antioxidant activity of the combined extracts in excess of their individual contributions.